How do we know justification is through faith alone?

The Biblical doctrine of justification is that it is a legal declaration by God that a sinner is righteous based on their faith in Christ, rather than any works of their own. Romans 10:6-8 indicates that righteousness comes from faith, and Galatians 3:11 clearly states that no one is justified by the law in the sight of God, affirming that the just shall live by faith. This illustrates that our right standing before God is based solely on Christ's finished work, making justification a gift received through faith alone.